The principal aim of the epidemiologic research proposed here is to test risk factors for the development of panic attacks. Utilizing a school-based prospective design in an adolescent population, this project will track a large cohort of ninth graders during the period which represents their highest risk for developing panic attacks. The specific aims of the project are to obtain incidence and prevalence data on panic attacks in high school-aged adolescents and prospectively test multiple risk factors for the development of panic attacks, including history of panic attacks, major depression or alcoholism in the parents and history of depression, high scores on a measure of anxiety sensitivity, history of parental separation or divorce, recent life events, sex, ethnicity, and elevated resting heart rate in the students. Approximately 2470 ninth graders representing the freshman classes from six senior high schools will be followed annually for three years. Outcome variables will include panic attacks, and the development of secondary substance abuse, depressive symptoms and phobic avoidance. The psychiatric diagnosis and demographic information for the parents and the students win be determined with structured psychiatric interviews using the Structured Clinical Interview for DSM-III-R. Anxiety sensitivity, phobic avoidance, substance use patterns and depressive symptoms will be evaluated by questionnaire. Resting heart rate will be measured by ECG machines. Data analysis will utilize survival curve analysis to estimate the risk which each hypothesized risk factor contributes towards the development of panic attacks. Predictors for the development of panic disorder, phobic avoidance, increased substance use and depressive symptoms after an initial panic attack will be examined in exploratory, hypothesis-generating analyses.